We have restricted changing the home currency because it will affect existing records. The following are the effects of changing the home currency,
i) The currency of all the existing records will be set with the new Home currency (say USD) and all the existing currency values will not be converted but just assigned with the new Home currency
ii) All the configured currencies will be deleted and only the new home currency USD will be available. Since the exchange rates are defined based on the home currency, changing the home currency will make those exchange rates invalid.
If you are comfortable with these effects, then please acknowledge. Once we receive your acknowledgement, we will change your home currency.